deducting cost of improvement to business truck

[reluctanttaxman]

The bed on the back of my work pickup truck, >6000 gvwr, consistently >85% business use,  is rusted out and needs to be replaced.   Standard mileage deduction was used the first year the truck was used in business,  then alternated between  actual expenses with SL/HY depreciation, and standard mileage deduction whichever was greater.  Truck is fully depreciated now so there is no depreciation contribution when actual expenses is used. 

A new aluminum flatbed body bed will be installed to replace the rusted out bed.  Cost is $5300 for the bed, $1100 for installation labor, and $1100 additional cost to sandblast and repaint rusted frame members. Overall cost $7500. 

There is some repair/maintenance aspect to the $7500 cost but it seems to dictate capitalizing the $7500 as a new asset with a 5 yr depreciation schedule (200 DB half year convention).  Is this the correct way to handle it?   Is depreciation of this new $7500 asset independent of whether standard mileage or actual expenses is used going forward for the truck itself?  And can Sec179 be used for the $7500 new asset cost if desired? thanks. 

[JamesG1]

You may depreciate the new $7,500 asset.  The total depreciation expense may not exceed the Maximum Depreciation Deduction for 2024 which is $20,400.  The depreciation of the improvement plus the depreciation reported for the original asset must not exceed the Maximum Depreciation Deduction for 2024.

IRS Publication 563 Travel, Gift, and Car Expenses, page 27 states:

Improvements

A major improvement to a car is treated as a new item of 5-year recovery property. It is treated as placed in service in the year the improvement is made. It doesn’t matter how old the car is when the improvement is added. Follow the same steps for depreciating the improvement as you would for depreciating the original cost of the car. However, you must treat the improvement and the car as a whole when applying the limits on the depreciation deductions. Your car's depreciation deduction for the year (plus any section 179 deduction, special depreciation allowance, and depreciation on any improvements) can’t be more than the depreciation limit that applies for that year.

The Maximum Depreciation Deduction chart is found at the top of page 29.